package com.thealgorithms.maths;
/*
 * Java program for Square free integer
 * This class has a function which checks 
 * if an integer has repeated prime factors
 * and will return false if the number has repeated prime factors.
 * true otherwise
 * Wikipedia: https://en.wikipedia.org/wiki/Square-free_integer
 *
 * Author: Akshay Dubey (https://github.com/itsAkshayDubey)
 *
 * */

import java.util.HashSet;
import java.util.List;

public class SquareFreeInteger {
    /**
     * This method returns whether an integer is square free
     *
     * @param number Integer value which is to be checked
     * @return false when number has repeated prime factors
     *         true when number has non repeated prime factors
     * @throws IllegalArgumentException when number is negative or zero
     */
	public static boolean isSquareFreeInteger(int number) {
		
		if(number <= 0) {
			//throw exception when number is less than or is zero
			throw new IllegalArgumentException("Number must be greater than zero.");
		}
		
		//Store prime factors of number which is passed as argument
		//in a list 
		List<Integer> primeFactorsList = PrimeFactorization.pfactors(number);
		
		//Create set from list of prime factors of integer number
		//if size of list and set is equal then the argument passed to this method is square free
		//if size of list and set is not equal then the argument passed to this method is not square free
		return primeFactorsList.size() == new HashSet<>(primeFactorsList).size();
	}
}
